Photosynthesis is the process in which living cells from plants and other organisms use sunlight to produce nutrients from carbon dioxide and water, the image below “Diagram of photosynthesis 1,” helps show this process. Photosynthesise generally creates oxygen as a by-product through the use of the green pigment, chlorophyll, found in the plant that helps this reaction occur. “Photosynthesis provides us with most of the oxygen we need in order to breathe. We, in turn, exhale the carbon dioxide needed by plants,” (factmonster,2017). This is able to show us why photosynthesis is so greatly needed to occur through plants in order to give one another essentials needed for continuity of life. “Plants perform photosynthesis because it generates the food and energy they need for growth and cellular respiration,” (photosynthesieeducation, 2016).
Photosynthesis is a cycle plants go through converting light into chemical energy for use later. Photosynthesis starts in the chloroplasts, they capture chlorophyll, an important chemical needed for photosynthesis. Chloroplasts also take water, carbon dioxide, oxygen and glucose. The chlorophyll is taken to the stroma, where carbon dioxide and water mix together to make oxygen and glucose. The oxygen keeps all species on earth alive because animal cells need an aerobic environment. (Rader, 1997). Photosynthesis captures electrons from water to energy-lacking carbon dioxide molecules, developing energetic sugar molecules. This is an example of an oxidation reduction process in the molecules. “The water loses electrons and becomes oxidized,” (Pearson, 2014). Photosynthesis uses light energy to move electrons from water to more energetic states in sugar molecules, therefore changing solar energy to chemical energy (Pearson, 2014). Photosynthesis happens in a unique process that is determined by what resources the plant has to produce this reaction. “Photosynthesis happens when water is absorbed by the roots of green plants and is passed to the leaves by the xylem, and carbon dioxide is achieved from air that enters the leaves through the stomata and disperses to the cells containing chlorophyll,” (factmonster,2017). This is able to show how the process happens whilst also “Diagram A” above shows photosynthesis in more detail, from this image it is noted that photosynthesis is the opposite of respiration, photosynthesis also happens at a much faster rate which means more oxygen is released than used. During this process it can be broken down into to stages of how photosynthesis works there is light dependent and light independent. “These reactions take place on the thylakoid membrane inside the chloroplast. During this stage light energy is converted to ATP (chemical energy) and NADPH (reducing power),” (photosynthesieeducation, 2016). Light dependant is the process in which the chloroplast trap light energy and convert it into chemical energy contained in NADPH and ATP, these two molecules are then used in the second stage of photo synthesis. It also has photosystem included to help this process, “The energy from light drives the electrons from the photosystem into a high-energy state. There are two photosystems, fittingly names photosystem I and photosystem II, situated in the thylakoid membrane of the chloroplast. The thylakoid membrane absorbs photon energy of different wavelengths of light,” (schmoop,2015). This process can be shown through “Diagrams B and C.” The second stage known as light independent is the process in which flows of energy and electrons initiated by light energy are depended upon, in this process NADPH provides the hydrogen atom that helps form glucose and ATP provides energy for this and other reactions used to synthesise glucose.
Action spectrum is also a very important part in the process of photosynthesis, the light in the action spectrum is what is absorbed by the plant in order for this reaction to occur. Different shades from the light spectrum are absorbed and the plant uses this energy from the light to process it into the rate of photosynthesis. This means that plants need certain spectrums of light in order for photosynthesis to occur at a proper rate. “An action spectrum defines the relative effectiveness of different wavelengths of light (colours) for light-dependent processes such as photosynthesis,” (facultyunlv,2016). An action spectrum is the rate of a physical activity plotted alongside wavelength of light. It shows which wavelength of light is most efficiently used in a specific chemical reaction. In terms of E. Nuttallii the main colours of wavelength are blue and red therefore reflecting green, therefore giving the plant its colour. The wavelengths can be affected by things like water, this shortens the wavelength and can affect the plants photosynthesis rate as the specific colour needed may have a shortened supply to help with the specific chemical reaction. This can be shown with the following images below to help represent how the wavelengths are affected and how they are used in “figures 1 &2”.
Overall this is able to show how important and how much light from the action spectrum is relied upon in photosynthesis. “Action spectrums describes the efficiency with which specific wavelengths produce a photochemical reaction. Photosynthesis involves the harvesting of light (absorption spectrum) and the subsequent photochemical and biochemical reactions. Meaning, an action spectrum describes the wavelengths that actually drive photosynthesis,” (heliospectra,2017). It can show the effect it has on photosynthesis if one of the wavelengths was to be taken away, it gives us not only a better understanding of how photosynthesis works but also the plant and how chlorophyll work and the different light spectrums that E. Nuttallii prefers for this reaction to occur.
There are many factors that can affect this process known as photosynthesis such as light intensity, temperature, climate and carbon dioxide levels these are the main factors that will affect the rate of photosynthesis. Light intensity is a very big factor into affecting the rate of photosynthesis. Due to light being a main factor needed in the process of photosynthesis in plants if it is altered to different intensity’s. The enzymes in the plant that use the sunlight to cause this reaction, if different intensities are placed upon those enzymes it can cause denaturing of the enzyme resulting in photosynthesis to not occur at a certain rate or at all. The image below, “Diagram 1,” shows the correlation between light intensity and photosynthesis. Temperature also affects photosynthesis, if it gets too warm the enzymes begin to denature. This means they are incapable to function correctly and the rate of photosynthesis decreases again, also at higher temperatures the stomata close to prevent water loss this then stops gas exchange which slows photosynthesis even further. “Diagram 2” is able to show this link between temperature and the rate of photosynthesis. Climate and co 2 are also known factors to affecting the rate of photosynthesis. This occurs because when the climate changes or isn’t the right environment for certain plants it means they aren’t getting the correct amount from resources such as sunlight therefore overall the affecting the rate because certain plants aren’t able to adapt to certain environments. Also if co2 levels aren’t correct for certain plants it can affect the rate of photosynthesis because it causes the plant to not synthesise as it needs co2 in combination with water to turn it into sugars and other compounds. The diagram below “Diagram 3” is able to show how co2 levels affect the rate of photosynthesis.
The plant Elodea is a common plant looked at to study the rate of photosynthesis and what factors affect it. Elodea come sin two common species, the one being looked at is Elodea Nuttallii, it is a water weed and has a wide climate range and tends to live in fresh water. Elodea is an underwater marine plant with oval shaped leaves grouped into clusters of 3 or 4 around the stem, it’s also an exceptional producer of oxygen. Elodea can grow in heights between 4 inches to 3 feet, depending on the depth of the body of water. Elodea reproduces by growing large buds in the springtime, relying very little on seed reproduction. (bmgscience. weebly,2017). The main factors being looked at is light intensity and temperature and how those factors affect the overall rate of photosynthesis in E. Nuttallii. Light intensity decreases with increased distance, this can be represented by this law and “Eqaution1.”
The formula shows how the light intensity is inversely proportional to the square of the distance from the light to the E. Nuttallii, therefore making the rate of photosynthesis directly proportional to the intensity of the light. Therefore, this is able to prove that when light intensity is increased so should the rate of photosynthesis. This can also show how light intensity is a significant factor in affecting the rate of photosynthesis. Photosynthesis is a chemical reaction that captures light energy and turns it into sugar. These sugars are used by plants as energy for many different things. The process of photosynthesis requires Light, Carbon dioxide and water. If any one of these things is limited in supply, then photosynthesis cannot happen. “When you increase the level of light, plants will photosynthesize more. But, if you have too much light, then the other 2 ingredients become limiting and photosynthesis can no longer increase with the level of light,” (scienceline,2016). With too little light, photosynthesis cannot occur as the plant suffers due to no production of sugars. There are many complicating interactions between plants and light therefore showing how the level of light is inversely proportional to the square of the distance from the E. Nuttallii sprig. “Plants need light energy to make the chemical energy needed to create carbohydrates. Increasing the light intensity will boost the speed of photosynthesis. However, at high light intensities the rate becomes constant,” (biology-igcse,2016). This is able to show the importance of sunlight in the reaction of photosynthesis therefore showing how much of a factor this is in terms of affecting photosynthesis. During this process Energy from the light is absorbed by chlorophyll is converted to ATP and H+, from this if the light intensity increases, the rate of photosynthesis increases. Though, the rate will not increase beyond a certain level of light intensity due to the rate of photosynthesis becoming a constant causing the rate of photosynthesis to stop.
Temperature also places a significant affect to the rate of photosynthesis as “Diagram 4” shows. Photosynthesis occurs in the chloroplast; enzymes work in this part of the cell to process the rate of photosynthesis. These enzymes can only work in certain conditions otherwise they denature therefore preventing the rate of photosynthesis to occur. That is the main way temperature affects it causing the rate to decrease. “Photosynthesis is a series of chemical reactions, Heat speeds up chemical reactions by adding kinetic energy to the reactants…Too much heat destroys enzymes–complex proteins which greatly increase the rate of photosynthesis,” (Bob Barber, 2001). Heat speeds up the process of photosynthesis–to a point. Once heat begins to destroy enzymes, photosynthesis drastically slows down therefore affecting the rate of this reaction. Cooler temperatures can also affect Enzymes; they are proteins that only work when they are in their proper three-dimensional shape. “This shape is not static like a concrete statue, but is constantly expanding and contracting like lungs that move with each breath. This flexibility is essential to how enzymes bind to other molecules and cause chemical reactions to happen on those molecules. Lowering the temperature slows the motion of molecules and atoms, meaning this flexibility is reduced or lost,” (Education. seattlepi,2014). Each enzyme has a zone of comfort, or optimal temperature range, within it works best at. As the temperature decreases, so does the enzyme’s activity. Enzymes are proteins that have a special three-dimensional shape. “Each enzyme has an ideal temperature range, meaning the enzyme has highest activity somewhere in the range of the middle. If the temperature is too far below or high above this range, the enzymes stop working,” (Education. seattlepi,2014). Enzymes work fastest when they are at the optimum temperature, but as the temperature gets outside the optimal range the enzyme’s activity begins to decrease. This can be shown in E.Nuttallii by “Diagram5” below.